Department of Chemistry, William Mong Institute of Nano Science and Technology, Bioengineering Graduate Program, The Hong Kong University of Science & Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China, and Department of Polymer Science and Engineering, Key Laboratory of Macromolecular Synthesis and Functionalization of the Ministry of Education, Institute of Biomedical Macromolecules, Zhejiang University, Hangzhou 310027, China

Acetylenic polymers: syntheses, structures, and functions.

In the chromatographic separation of enantiomers the order of elution is determined by the strength of diasteromeric interactions between the components of the mixture and a chiral stationary phase. For analytical purposes, it is ideal to have the minor component elute first, whereas in the preparative mode a faster elution of the major component is desirable. Here we describe a stationary phase constructed from a polyacetylene that bears 2,2'-bisphenol-derived side chains in which chirality can be switched in the solid state prior to use. Both the macromolecular helicity of the polymer backbone and the axial chirality of the side chains can be switched in the solid state by interaction with a chiral alcohol, but importantly are maintained after removal of the chiral alcohol because of a memory effect. The chiral stationary phase thus prepared was used to separate the enantiomers of trans-stilbene oxide with the enantiomer elution order determined by the preseparation treatment.

Switchable enantioseparation based on macromolecular memory of a helical polyacetylene in the solid state

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/34142/1/tamura.pdf

The role of rusts in corrosion and corrosion protection of iron and steel

Polymerization of substituted acetylenes and features of the formed polymers

Characterization, synthesis and catalysis of hydrotalcite-related materials for highly efficient materials transformations

Stereoregular polymerization of (p-3-methylbutoxy)phenylacetylene (p3MBPA) was successfully performed with a [Rh(NBD)Cl] 2 catalyst to afford poly(p-3-methylbutoxy)phenylacetylene (Pp3MBPA) having a cis-transoid form in high yields when ethanol or 1-butanol in the presence of triethylamine was used as the polymerization solvent. The resulting cis polymer was composed of a pseudohexagonal structure called columnar as π-conjugated self-assembly or π-conjugated self-organization in the solid state. The columnar polymer underwent isomerization from the predominant cis to trans form when compressed at 100 kg/cm 2 at room temperature. The pristine polymer and the compressed polymer were characterized in detail using 1 H NMR, wide-angle X-ray diffraction, laser Raman, electron spin resonance, and diffuse reflective UV-vis methods. Consequently, the data showed that the absorption maximum of the π-conjugated columnar polymer appears in an extremely longer wavelength region, ie., at 490 nm, despite the cis form compared with 450 nm of the amorphous cis form. In the solid state, a large blue shift of the absorption maximum was found to be induced when the columnar structure was destroyed by compression to produce a trans-transoid form which has planar zigzag π-conjugation sequences. The pristine columnar polymer showed the λ max as an entire absorption at notably longer wavelength so that the chromophore of the π-conjugated columnar polymer is not to be simply attributed to the primary structure, e.g., a repeated double-single bond structure, but rather should be ascribed to that of aggregated molecules called the π-conjugated columnar as self-assembly or self-organization. This explanation is a new concept with respect to the color of π-conjugated columnar polymers and is very important for the molecular design of electroluminescense (EL) and nonlinear optical (NLO) materials which are used at present in the solid state.

Origin of color of π-conjugated columnar polymers. 1. Poly(p-3-methylbutoxy)phenylacetylene prepared using a [Rh(norbornadiene)Cl]2 catalyst

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/14585/1/JCIS.pdf

Formation of hydrotalcite in aqueous solutions and intercalation of ATP by anion exchange

Copolymers of phenylacetylene (PA) and para-nitrophenylacetylene (pNPA), named poly(PA-co-pNPA), were obtained in different PA/pNPA ratios and different reaction conditions with Rh(I) catalysts. The structure of the copolymers was investigated with IR, laser Raman, 1H NMR, electron spin resonance (ESR), and diffuse reflective ultraviolet–visible (DRUV) light spectroscopies. The pristine polymers had a cis–transoidal structure as the predominant conformation with some trans sequences. Detailed ESR studies supported by computer simulation and conformation analysis have suggested that the trans sequences were due to pNPA sequences and that the cis-CC bond sequences of pNPA were associated with a stabilized cis radical formed by four to five of pNPA monomers. This particular stabilization was probably the reason for the higher reactivity of pNPA as compared with PA. These cis sequences were preferentially cleaved to generate π radicals. The compression and, to a minor extent, thermal treatment of poly(PA-co-pNPA) samples induced a cis-to-trans isomerization, leading to a trans–transoidal form with a planar zigzag structure and with a conjugation length up to n = 24 repeat units, determined by DRUV and Raman experiments. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2365–2376, 2004

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Poly(2-ethynylthiophene) was stereoregularly prepared with a Rh complex catalyst, [Rh(norbornadiene)Cl]2, to selectively produce the cis−transoid isomer in high yields when triethylamine was used a...

Photoinduced Cis-to-Trans Isomerization of Poly(2-ethynylthiophene) Prepared with a [Rh(norbornadiene)Cl]2 Catalyst. 1H NMR, UV, and ESR Studies

Highly stereospecific polymerization of a novel sulfur containing aromatic acetylenes, that is, (p-n-octylthiophenyl)acetylene (pOctSPA), was successfully performed using the Rh complex, [Rh(norbornadiene)Cl]2-TEA, catalyst in the presence of various solvents under mild conditions. The resulting polymers were characterized in detail by 1H NMR, ESR, laser Raman, diffuse reflective UV-Vis (DRUV-Vis), and wide angle X-ray diffraction methods. The data showed that the resulting polymers bear cis-transoid form, which can induce the cis-to-trans isomerization when the cis polymers are subjected to pressure at room temperature under vacuum, breaking rotationally the cis CC bonds in the main-chain giving two kinds of π-radicals, the so-called cis radical and trans radical as the origin of a polymer magnet like a novel spin glass material. Further, the resulting cis poly(acetylene)s were found to have a helical main-chain, which is packed in pseudohexagonal crystal called π-conjugated columnar or nano π-conjugated columnar as a novel color controllable material. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2836–2850, 2005

Yasuteru Mawatari

Papers

Origin of color of π-conjugated columnar polymers. 1. Poly(p-3-methylbutoxy)phenylacetylene prepared using a [Rh(norbornadiene)Cl]2 catalyst

Formation of hydrotalcite in aqueous solutions and intercalation of ATP by anion exchange

Copolymers of phenylacetylene and para‐nitrophenylacetylene with nonlinear optical properties: Further insight on the conformational structure

Photoinduced Cis-to-Trans Isomerization of Poly(2-ethynylthiophene) Prepared with a [Rh(norbornadiene)Cl]2 Catalyst. 1H NMR, UV, and ESR Studies

Origin of the color of π‐conjugated columnar polymers: Poly(p‐n‐octylthiophenyl)acetylene prepared using a [Rh(norbornadiene)Cl]2 catalyst